docs: def proxy_manager_for(self, proxy, **proxy_kwargs):
          """Called to initialize the HTTPAdapter when a proxy is used."""
          try:
              proxy_kwargs['ssl_version'] = ssl.PROTOCOL_TLS
          except AttributeError:
              proxy_kwargs['ssl_version'] = ssl.PROTOCOL_SSLv23
          return super(SSLAdapter, self).proxy_manager_for(proxy, **proxy_kwargs)